HEIDI DOUGLASS | h.douglass@unsw.edu.au
Researchers in the Brain & Ageing Laboratory at UNSW Sydney’s Centre for Healthy Brain Ageing (CHeBA) have discovered that low levels of blood lipids in people over 95 years of age could signify a unique lipid profile that may be associated with a longer lifespan.
The findings, published in PLOS One, examined how lipids in plasma are affected by age and sex in a group of healthy human individuals.
Lipidomics is an emerging field which involves the quantification of small molecules known as lipids. Lipids have important roles in cells, tissues and organ physiology due to their unique membrane organising properties – providing the cells with specialised sub-compartments. Lipids are also involved in energy storage, cellular signalling and hormonal regulation. Altered lipid metabolism has been associated with several age-related diseases including Alzheimer’s disease.
Although lipidomics is becoming increasingly popular as a screening tool for understanding disease mechanisms, it Is largely unknown how the lipidome naturally varies by age and sex.
The study used plasma from 100 subjects with an apolipoprotein E (APOE) E3/E3 genotype; aged between 56 to 100 years.
Lead author, CHeBA PhD student Matthew Wong, said that untargeted analysis was performed by liquid chromatography coupled-mass spectrometry and data processing using LipidSearch software.
Head of the Brain & Ageing Laboratory, Dr Nady Braidy, said the research found that plasma lipids change with age and are affected by sex in healthy individuals.
“Most lipids declined with age, more so in males than females,” said Dr Braidy.
Females had higher levels of certain lipids such as low-density and high-density lipoprotein, total cholesterol, sphingomyelins and the phospholipid docosahexaenoic acid (DHA). DHA is important for maintaining brain health and cognition, and higher levels of DHA has been shown to reduce mortality due to late-life disease.
“It is likely that sex may have a major impact on lipids in age-related diseases such as Alzheimer’s disease, affecting risk and severity,” said Dr Braidy.
Surprisingly, the study found minimal association between lipid levels and body mass index (BMI) for most lipid classes.
“While BMI is typically associated with obesity and related conditions such as diabetes and cardiovascular disease, the exact relationship between BMI and lipid levels in ‘healthy’ individuals remains to be elucidated,” said Dr Braidy.
Co-Director of CHeBA, Professor Perminder Sachdev, said the results suggest substantial age and sex-related changes in the plasma lipidome of healthy individuals during the second half of the human lifespan.
“Globally low levels of blood lipids in the ‘oldest old’ subjects over 95 years could signify a unique lipidome associated with extreme longevity,” said Professor Sachdev.
Matthew Wong is a CHeBA PhD student.
